Stabilizing foot

ABSTRACT

Provided herein is an improved support device for stabilizing an article of furniture, appliance or other equipment. In one arrangement, the device is connectable to the bottom of existing furniture legs eliminating the need to provide customized legs. That is, the overall height of the device is such that a table or chair incorporating the device is not altered to a degree that changes the basic functionality of the table or chair. Stated otherwise, the device forms a stabilizing foot that is connectable to the legs of a chair or table without substantially altering the seat height of the chair or the top of the table.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority and the benefit of the filing date under 35 U.S.C. 119 to U.S. Provisional Application No. 61/161,866, entitled, “STABILIZING FOOT,” filed on Mar. 20, 2009, the contents of which are incorporated herein as if set forth in full.

FIELD OF INVENTION

The present invention relates in general to a furniture support. More specifically, the invention is directed to a new improved support that automatically adjusts to retard rocking or tilting of a piece of furniture on an uneven floor.

BACKGROUND OF THE INVENTION

Furniture bases which contact the floor at more than three places are frequently unstable and tend to rock about the line connecting two of the contact points. To alleviate such rocking, different types of adjustable furniture supports have been designed and marketed. In some cases the supports were self-adjustable while in other cases they were manually adjustable. Where the table or piece of furniture was frequently moved on an uneven floor, as for example, in a restaurant, the manually adjustable supports are unsatisfactory because the frequent need for adjustment. On the other hand, self-adjusting furniture supports of prior art have typically been expensive to manufacture, fragile and susceptible to damage and/or inadequate for their intended function. Furthermore, many of these manual and/or self-adjusting supports have required that one or more legs of a furniture piece be custom made to accommodate the adjusting device.

SUMMARY OF THE INVENTION

Provided herein is an improved support device for stabilizing an article of furniture, appliance or other equipment. In one arrangement, the device is connectable to the bottom of existing furniture legs eliminating the need to provide customized legs. That is, the overall height of the device is such that a table or chair incorporating the device is not altered to a degree that changes the basic functionality of the table or chair. Stated otherwise, the device forms a stabilizing foot that is connectable to the legs of a chair or table without substantially altering the seat height of the chair or the top of the table.

Typically, an article of furniture incorporating the stabilizing foot will have such a foot attached to each leg that contacts a floor. That is, a four legged table will use four stabilizing feet. When one of the stabilizing feet is suspended above a floor surface, the suspended stabilizing foot utilizes a combination of a resilient spring and a hydraulic cylinder/piston arrangement to extend a base of the foot to contact the floor surface and resist subsequent compression. When no load is applied, the spring(s) apply a biasing force between the piston and the base of the cylinder (which may also form the base of the foot) that moves the base away from the piston. The piston utilizes a one-way flow assembly that allows for hydraulic fluid within the cylinder to flow past the piston in one direction (i.e., during foot extension) with little impedance while providing significant impedance to fluid flow in the opposite direction (i.e., during foot compression).

The spring functions to extend the foot in a condition of no or little load. That is, it is not the function of the spring to support the table, but rather to extend the foot to contact the floor. In this regard, if three feet of a four-legged table are in contact with the floor, the springs within those feet may collapse allowing the pistons in those feet to move substantially adjacent to the base of the cylinder and foot. That is, neither the spring nor the fluid supports the compressed feet. In such an arrangement, a shaft or stud interconnected to the piston and interconnectable to the bottom of a furniture leg may provide a continuous solid support between the floor and the leg. That is, when the piston is located at or near the bottom of the cylinder, an end of the shaft may be supported by the base of the foot or a stop connected to the base and provide a continuous solid support between the floor and the leg.

In contrast, a foot that is suspended above the floor (or possibly two opposing feet) bears little or no weight and the springs therein are not collapsed. The springs in such a suspended foot are operative to push the base of the cylinder away from the piston allowing the foot to contact the floor. To permit this expansion, the piston permits bypass flow allowing the spring to readily expand when no load is applied to the foot. Once the foot contacts the floor, a weight applied over that leg/foot would cause fluid to flow in the other direction past the piston collapsing the foot if not for the limiting one-way flow through the piston. When the foot is expanded by the springs such that the base of the foot contacts the floor, the fluid within the piston provides support if weight is applied above that leg of the table. In this instance, the shaft interconnecting the foot to the table does not form a continuous support to the floor through the foot. Rather, this rod, which is interconnected to the piston, is supported by fluid within the cylinder.

To achieve one-way flow, the piston of the stabilizing foot utilizes a check valve or other arrangement that limits fluid flow in the collapse direction such that the stabilizing foot collapses very slowly. Furthermore, if the stabilizing foot slowly collapses in response to an applied weight, an opposing foot will be lifted off the ground, and the spring in that foot will rapidly expand to maintain that foot in contact with the ground. The flow around or through the piston in the cylinder may be limited to the point that such slow tilting of a table is barely noticeable and/or does not upset elements (e.g., wine glasses) supported on the tabletop.

The ability to limit flow in one direction while permitting substantially unfettered flow in another direction may be accomplished utilizing one or more check valves disposed through the piston positioned within the cylinder. Such check valves may allow fluid flow in one direction while allowing limited flow in the opposing direction. Alternatively, the piston may be sized and/or shaped such that a check valve may allow flow in one direction and no flow in the other. In such an arrangement, fluid may pass around the interface between the piston and the cylinder to allow the slow/controlled compression of the foot. That is, if a compressing force is applied over an extended foot, this force is resisted by the reaction of the piston against the hydraulic fluid and the one-way flow device to prevent the flow of hydraulic fluid past the piston. However, if the compressing force is maintained, fluid eventually flows past the piston (i.e., by-pass flow), for instance, between the outer periphery of the piston and the walls of the cylinder, at a rate dependent upon the clearance between the piston periphery and the walls for a given compressing force. Eventually, the device is contracted to the point where the shaft abuts the base of the cylinder. The piston may be shaped to provide a desired rate of by-pass flow. For instance, a piston disposed in a round cylinder may not be perfectly round to provide a by-pass flow channel. For instance, the piston may be ovular and/or include various lobes.

The ability to make a compact stabilizing foot that does not substantially alter the height of existing furniture is aided by the disposition of the biasing/spring member within the fluid cylinder. That is, the spring may be disposed in the fluid cylinder between the piston and the base of the cylinder. This allows utilizing the structure of the fluid cylinder for both expansion and compression functionality. In one particular arrangement, crescent springs are utilized (e.g., spring washers) to provide the biasing force. Such crescent springs may be separated by one or more flat washers. Furthermore, multiple crescent springs may be stacked together to increase the spring bias force applied to the piston depending on the intended use of the foot. That is, when interconnected to a heavy table, it may be desirable that the spring biasing force is increased. Furthermore, use of the spring washers allows for the shaft to pass through the control apertures of the spring washers to rest on the base of the cylinder when compressed. Use of spring washers instead of, for example, a coil spring allows for providing an increased spring force over a shorter displacement length.

It will be appreciated that the use of the washer springs reduces the length of a spring necessary to provide a restoring force to a stabilizing device and thereby permits generating a very compact stabilizing foot in accordance with the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention and further advantages thereof, reference is now made to the following detailed description taken in conjunction with the drawings in which:

FIG. 1 illustrates one embodiment of a stabilizing foot in accordance with the present invention.

FIGS. 2A-2C illustrate perspective, side and cross-sectional views, respectively, of the stabilizing foot of FIG. 1.

FIG. 3 illustrates one embodiment of a stabilizing foot in accordance with the present invention.

FIGS. 4A-4C illustrate perspective, side and cross-sectional views, respectively, of the stabilizing foot of FIG. 3 in an extended position.

FIGS. 5A-5C illustrate perspective, side and sectional views, respectively, of the stabilizing foot of FIG. 3 in a compressed/collapsed position.

FIG. 6 illustrates a non-round piston that may be utilized by the stabilizing foot.

DETAILED DESCRIPTION

Provided herein is an improved support device for stabilizing an article of furniture, appliance or other equipment. In one arrangement, the device is connectable to the bottom of existing furniture legs eliminating the need to provide customized legs. That is, the overall height of the device is such that a table or chair incorporating the device is not altered to a degree that changes the basic functionality of the table or chair. Stated otherwise, the device forms a stabilizing foot that is connectable to the legs of a chair or table without substantially altering the seat height of the chair or the top of the table.

Typically, an article of furniture incorporating the stabilizing foot will have such a foot attached to each leg that contacts a floor. That is, a four legged table will use four stabilizing feet. When one of the stabilizing feet is suspended above a floor surface, the suspended stabilizing foot utilizes a combination of a resilient spring and a hydraulic cylinder/piston arrangement to extend a base of the foot to contact the floor surface and resist subsequent compression. When no load is applied, the spring(s) apply a biasing force between the piston and the base of the cylinder (which may also form the base of the foot) that moves the base away from the piston. The piston utilizes a one-way flow assembly that allows for hydraulic fluid within the cylinder to flow past the piston in one direction (i.e., during foot extension) with little impedance while providing significant impedance to fluid flow in the opposite direction (i.e., during foot compression).

FIGS. 1 and 2A-C illustrate a first embodiment of a stabilizing foot 100 in accordance with various aspects of the presented inventions. The stabilizing foot 100 includes a cylinder 1 that has an internal bore 15 that is adapted to receive a piston 2. In this regard, the piston 2 has an outside diameter that is substantially equal to the inside diameter of the bore 15. However, as will be discussed herein, working fluid within the cylinder may bypass around the outside surface of the piston 2 to provide desired functionality. The outside surface of a lower end of the cylinder 1 is threaded for receipt within an inside surface of a threaded base 5. The bottom surface of the base 5 is flat for disposition on a support surface (e.g., floor). Generally, the central axis of the internal bore 15 will be substantially normal to the bottom surface of the base 5. Disposed between the bottom edge of the cylinder 1 and the bottom inside surface of the base 5 are one or more O-rings 8, Such O-rings maintain a working fluid within the cylinder. The cylinder 1 and base 5, when connected, collectively define a housing that is fluid-tight to maintain a working fluid therein. Such working fluids may include liquids as well as compressed gases. Generally, fluid choice is a design specification and may be selected based on flow rates through the piston 2, as discussed herein. Generally, more viscous fluids, such as liquids (e.g., oils), provides slower response times than gases.

Interconnected to the piston 2 is a shaft. A top end of this shaft 3 is threaded for receipt within the bottom of a table leg or a chair leg. This shaft or stud 3 extends through the top of the cylinder 1. One or more O-rings 6 may be inserted at this interface to prevent the working fluid within the cylinder from bleeding through this interface, It will be appreciated that many tables or chairs have a threaded bottom aperture that allows for attaching a foot. Such preexisting feet may be removed, and the stabilizing foot 100 may be threaded therein to replace the existing feet and thereby provide a self-leveling table, chair, etc.

A lower end of the threaded stud or shaft 3 is connected to a top surface of the piston 2. A screw 7 passes through a central aperture in the piston 2 and is received within a threaded bottom aperture (not shown) of the stud 3 to interconnect the stud 3 to the piston 2. Interposed between the head of the screw 7 and the bottom surface of the piston 2 is a base stop 9. As will be discussed herein, this base stop is operative to rest on an upper surface of the threaded base 5 when the stabilizing foot 100 is collapsed.

Also interconnected to the surface of the piston 2 are one or more check valves 4. These check valves 4 in the present embodiment are resilient flappers that are secured by a securing screw 10. The securing screw 10 is inserted into a threaded aperture within the surface of the piston. The flapper 4 extends over a bleed aperture 13 that extends through the piston 2. This permits fluid within the cylinder 1 to pass through the piston 2 at a controlled rate. The size of this aperture may vary based on, for example, the viscosity of the working fluid. The present embodiment utilizes two check valves 4 to permit hi-directional fluid flow. In some embodiments, the piston utilize a single bleed aperture that permits a one-way flow. In such an arrangement, flow may be permitted through the piston in a first direction and flow in a second direction may be forced to bleed around the interface between the outside surface of the piston 2 and the inside surface of the cylinder 1.

Disposed below the bottom surface of the piston 2 and the top surface of the base 5 is a crescent spring assembly 11. These springs bias the piston 2 upward into the cylinder 1 and away from the floor of the base 5 when the stabilizing foot does not support weight. FIG. 2C illustrates a side and cross-sectional view of the embodiment of FIG. 1. As shown, the stabilizing foot 100 is experiencing no significant weight. Accordingly, the spring assembly 11 has extended the piston 2 to the top of the interior bore of the cylinder 1, thereby lifted the base stop 9 off of the surface of the base 5. That is, the spring has exerted a force on the piston forcing working fluid through or around the piston such that the piston rests against the end of the internal bore.

An assembled stabilizing foot functions as follows. The crescent spring assembly 11 is of sufficient strength to push the base 5 and cylinder (e.g., housing) away from the piston/check valve assembly 2 until the top of the piston 2 makes contact with the top/closed end of the internal bore in the cylinder 1. See FIG. 2C. When attached to table legs or the base of other devices that are resting on the floor the stabilizing foot functions as follows. The crescent spring assembly 11 is not of sufficient strength to support a table or other device to which it is attached, causing the crescent spring assembly 11 to compress until the stop 9 makes contacts the floor/upper surface of the base 5. Accordingly, the fluid passes through or around the piston until the majority of the fluid is above the piston. When the table or other device is resting on an uneven surface, two or three feet will bottom out, leaving one or two feet in contact with the floor but not fully compressed. If additional weight is applied to one of the stabilizing foot assemblies that are not fully compressed, hydraulic medium will flow through the top check valve until the foot is fully compressed. Simultaneously, on the opposing foot, the base 5 will extend away from the piston 2, keeping the base 5 in contact with the floor.

The check valve(s) are designed to cause the base 5 to extend or move away from the piston 2 at a rate faster than the piston 2 can be compressed towards the bottom of the counter bore in the cylinder 1. Thus all four feet of a table will remain in contact with the floor, stabilizing the table or other device from any rocking motion that would occur if the floor surface were not flat.

The components of the stabilizing foot may be made from metal or plastic. The spring 11 is shown as a crescent washer spring pack but could be a coil, wave washer or other spring mechanism. The stop 9 serves to keep the crescent spring assy. II from compressing past its maxim deflection and could be incorporated as part of the piston 2 or base 5.

FIGS. 3, 4A-C and 5A-C illustrate another embodiment of the stabilizing foot 100. In this embodiment, the cylinder 1, piston 2, check valve 4, stop 9 and base 5 may each be made of an injected molded plastic. Furthermore, the top O-ring 6 is incorporated within the threaded stud 3. In this embodiment, the base 5 incorporates a snap-fit feature that mates with a lip disposed around an outside surface of the cylinder 1. Again, when interconnected, an O-ring 8 is compressed between the mating surfaces of the cylinder 1 and base 5 to maintain a fluid-tight interface between the cylinder 1 and base 5. Again, the base and cylinder collectively define a housing that houses the piston 2 and working fluid. In addition, the base 5 incorporates a raised ring 14 on its upper surface that allows for aligning the crescent springs 11 during assembly.

Generally, the embodiment of FIG. 3 operates similar to that described in relation to FIG. 1. However, in this embodiment, the screw 7, which interconnects the stop 9 to the bottom of the piston 2 (and which also interconnects the stud to the top of the piston 2), passes through a central aperture in the check valve/flapper 4. In this regard, a separate screw is not needed to maintain the check valve relative to the piston. However, to maintain alignment of the check valve, one or more pins may pass through the base 5 and/or check valve through apertures aligned thereon. See, e.g., FIG. 6. In any arrangement, the working portion of the check valve 4 extends over the aperture 13 passing through the piston 2. As shown, this single check valve assembly provides one-way fluid flow through the piston 2. Accordingly, fluid flow in the other direction must pass around the outside surface of the piston 2. In this particular embodiment, the piston is a lobed piston that allows for fluid flow to pass at a controlled rate around the outside surface of the piston. This is further discussed below.

FIGS. 4A-C and 5A-C illustrate side and cross-sectional views of the stabilizing foot 100 of FIG. 3 in extended and collapsed orientations, respectively. Specifically, FIGS. 4A-C illustrates the stabilizing foot in a condition where the stabilizing foot is not supporting weight and the springs 11 extend the piston 2 to the end of the counter bore within the cylinder 1. Accordingly, the stop 9 and the bottom of the screw 7 are raised off the bottom surface of the base 5.

FIGS. 5A-C illustrate a condition where the stabilizing foot 100 is bearing weight and the spring assembly 11 is collapsed. As shown, in this orientation, the bottom of the screw and the stop 7, 9 rest on the upper surface of the base 5. In such an arrangement, when weight is applied to the stabilizing foot via the threaded stud 3, fluid passes through the aperture 13 of the piston 2, allowing the piston to move toward the bottom of the counter bore within the cylinder.

FIG. 6 details features of a lobed piston. In this embodiment the piston has a “tri-lobe” feature where there are three raised and three reduced diameter sections, located at 120 degrees from each other. The reduced diameter sections serve to allow fluid flow and eliminate the need of a top check valve. The piston 2 also incorporates a locating feature to orient the check valve 4 over the check valve aperture in the piston 2. It will be appreciated that the above embodiments may utilize either a lobed piston or a circular piston. That is, the piston and the internal bore may be correspondingly shaped.

The overall height of the housing and the stoke length of the shaft and piston may be scaled to any desired application. In applications where it is desirable to minimize the overall height of the device, such as incorporating the device onto existing furniture, the size of the housing may range between about 0.75 inches and about 1.25 inches. This short height allows the stabilizing foot to be incorporated onto existing articles of furniture (e.g., replacing existing feet) without significantly adjusting the overall height of the article. In such arrangements, the piston may have a stroke range between about 0.15 inches and about 0.4 inches.

The foregoing description of the present invention has been presented for purposes of illustration and description. Furthermore, the description is not intended to limit the invention to the form disclosed herein. Consequently, variations and modifications commensurate with the above teachings, and skill and knowledge of the relevant art, are within the scope of the present invention. The embodiments described hereinabove are further intended to explain best modes known of practicing the invention and to enable others skilled in the art to utilize the invention in such or other embodiments and with various modifications required by the particular application(s) or use(s) of the present invention. It is intended that the appended claims be construed to include alternative embodiments to the extent permitted by the prior art. 

1. A stabilizing foot for stabilizing a table, chair, appliance or other device supported by feet, comprising: a housing including: a base having a bottom surface for contacting a floor surface; a cylinder attached to the base and having an internal bore, wherein a central axis of the an internal bore is substantially normal to the bottom surface of the base; a piston disposed within the internal bore of the cylinder, the piston including a one-way flow element for permitting fluid flow in a first direction across the piston and restricting fluid flow in a second direction across the piston; a shaft assembly having a lower end connected to the piston and an upper end extending out of an upper portion of the housing; and a bias force element disposed within the internal bore of the cylinder between a bottom surface of the piston and an upper surface of the base; and a working fluid substantially filling the internal bore of the cylinder, wherein the base and cylinder are fluidly sealed to maintain the working fluid within the internal bore.
 2. The device of claim 1, wherein the one-way flow element comprises: a check valve.
 3. The device of claim 1, wherein the upper end of the shaft is threaded.
 4. The device of claim 1, wherein the bias force element comprises: a spring.
 5. The device of claim 4, wherein the spring comprises: at least one spring washer.
 6. The device of claim 4, further comprising a stop interconnected to a bottom surface of the piston, wherein a lower end of the stop is disposable through a central aperture of the at least one spring washer.
 7. The device of claim 6, wherein when the spring is in a compressed state, the stop is in physical contact with the upper surface of the base.
 8. The device of claim 1, wherein a periphery of the piston is conformably shaped with an inside periphery of the internal bore of the cylinder.
 9. The device of claim 1, wherein a periphery of the piston is differently shaped than an inside periphery of the internal bore of the cylinder.
 10. The device of claim 9, wherein the periphery of the piston includes at least first and second lobes, wherein an interface between the lobes has a diameter measured form a center of the piston that is less than the diameter of the lobes as measured form the center of the piston.
 11. The device of claim 1, wherein an overall height of the housing is between about 0.75 inches and about 1.25 inches.
 12. The device of claim 1, wherein the piston and shaft have a movement range of between about 0.15 inches and about 0.4 inches.
 13. The device of claim 1, wherein a lower outside surface of the cylinder is threaded for receipt within a threaded inside surface of the base.
 14. The device of claim 1, wherein a lower outside surface of the cylinder comprises an annular lip, wherein the annular lip is received in a snap fit arrangement with an inside surface of the base.
 15. A stabilizing foot for stabilizing a table, chair, appliance or other device supported by feet, comprising: a housing including: a base having a bottom surface for contacting a floor surface; a cylinder attached to the base and having an internal bore, wherein a central axis of the an internal bore is substantially normal to the bottom surface of the base; a piston disposed within the internal bore of the cylinder, the piston including: a fluid flow aperture passing through the piston from a top surface to a bottom surface; a one-way flow element for permitting fluid flow in a first direction through the fluid flow aperture; a shaft assembly having a lower end connected to the top surface of the piston and an upper end extending out of an upper portion of the housing, wherein the upper end of the shaft is threaded; and a stop element attached to the bottom surface of the piston; a spring washer pack disposed within the internal bore of the cylinder between the bottom surface of the piston and an upper surface of the base, wherein the stop element is aligned with a central aperture of the spring washer pack; and a working fluid substantially filling the internal bore of the cylinder, wherein the base and cylinder are fluidly sealed to maintain the working fluid within the internal bore.
 16. The device of claim 15, wherein a periphery of the piston is differently shaped than an inside periphery of the internal bore of the cylinder.
 17. The device of claim 16, wherein the periphery of the piston includes at least first and second lobes, wherein an interface between the lobes has a diameter measured form a center of the piston that is less than the diameter of the lobes as measured form the center of the piston.
 18. The device of claim 5, wherein when the spring washer pack is in a compressed state, the stop element is in physical contact with the upper surface of the base.
 19. The device of claim 15, wherein an overall height of the housing is between about 0.75 inches and about 1.25 inches.
 20. The device of claim 15, wherein the piston and shaft have a movement range of between about 0.15 inches and about 0.4 inches. 